Mitogenome recovered from a 19th Century holotype by shotgun sequencing supplies a generic name for an orphaned clade of African weakly electric fishes (Osteoglossomorpha, Mormyridae)

<i>Heteromormyrus</i> Steindachner, 1866, a genus of Mormyridae (Teleostei: Osteoglossomorpha), has been monotypic since the description of <i>Heteromormyruspauciradiatus</i> (Steindacher, 1866) from a single specimen. No type locality other than "Angola" was given and almost no specimens have been subsequently identified to this species. In order to investigate the relationship of this taxon to fresh specimens collected in Angola and elsewhere, whole genome paired-end sequencing of DNA extracted from the holotype specimen of <i>Heteromormyruspauciradiatus</i> was performed and a nearly complete mitogenome assembled from the sequences obtained. Comparison of cytochrome oxidase I and cytochrome <i>b</i> sequences from this mitogenome to sequences from recently collected material reveal that <i>Heteromormyruspauciradiatus</i> is closely related to specimens identified as <i>Hippopotamyrusansorgii</i> (Boulenger, 1905), <i>Hippopotamyrusszaboi</i> Kramer, van der Bank & Wink, 2004, <i>Hippopotamyruslongilateralis</i> Kramer & Swartz, 2010, as well as to several undescribed forms from subequatorial Africa collectively referred to in the literature as the "<i>Hippopotamyrusansorgii</i> species complex" and colloquially known as "slender stonebashers." Previous molecular phylogenetic work has shown that these species are not close relatives of <i>Hippopotamyruscastor</i> Pappenheim, 1906, the type species of genus <i>Hippopotamyrus</i> Pappenheim, 1906 from Cameroon, and are thus misclassified. <i>Hippopotamyrusansorgii</i> species complex taxa and another species shown to have been misclassified, <i>Paramormyropstavernei</i> (Poll, 1972), are placed in genus <i>Heteromormyrus</i> and one genetic lineage from the Kwanza and Lucala rivers of Angola are identified as conspecific <i>Heteromormyruspauciradiatus</i>. Three additional new combinations and a synonymy in Mormyridae are introduced. The morphological characteristics and geographical distribution of the genus <i>Heteromormyrus</i> are reviewed. The electric organ discharges (EODs) of <i>Heteromormyrus</i> species are to be treated in a separate study.